Easy kill
In the rooftop battle, if you knock down a man, you can throw him off the building, killing him.

When you are being attacked by someone, press "Crouch" + "Strong Attack" ( [Kick] ). You will spin with your leg out while crouching and knock them down, which will make it easy to pick them up and throw off a surface, stomp on them, pick them up then attack, or just throw them into a wall. Note: This works very well if large crowds are attacking. If they jump when you do this and you miss, either kick them and do it again or try it again immediately (spin with your leg out while crouching). Usually, Precrime with blue armbands will jump.

Enable the "Maximum ammunition" code. Buy the puke grenade and use it to make your enemies unconscious. Then, pick them up and you can throw them around, punch them, and use them as a body guard . Note: You must quickly pick them up, as they stay unconscious for a limited amount of time.

Defeating Nikki Jameson
Note: You must be able to get to the top floor. On the last level, once you are on the top floor, jump onto the space that you can stand on the pit that falls to the bottom. Make sure that you do not fall in. Eventually, Nikki will use the attack where she jumps onto your head and grabs it. When she does this, you will both fall into the pit, but the ending sequence will appear before you die. Note: She may just knock you with normal punches and kicks, but when you get close to falling, just reposition John.

Suspect: Nikki Jameson level: Prevent Nikki attacks
A Wasp Launcher is required for this trick. At the end of the level, where you turn the corner and confront Nikki, partially creep through the door. Do not go all the way or you will trigger the ending scene. Fire the Wasp Launcher so the projectiles will lock on to Nikki and she will run up out of the hallway. She is invincible, but will not attack Barry. Note: If you walk through the hall, you will end the level as normal.

Practice against police
When in the level where there is a revolt with gangsters against the normal cops, after defeating the PC units, side with the gangsters. You will be able to practice fighting moves on the normal police.